---
title: "API documentation (OpenAPI)"
description: "The OpenAPI document of the HTTP API with the JSON Schema of all actions, and how to browse it with Swagger UI."
canonical: open-api.html
navigation-title: "OpenAPI"
---

<a id="usage-openapi"></a>

<a id="api-documentation-openapi"></a>

# API documentation (OpenAPI)

The endpoint `GET /typo3/api/v1/schema` returns an
[OpenAPI](https://www.openapis.org/) document of all actions of the HTTP API.
It contains the JSON Schema of their parameters and results, and their scopes.
The document gives each error of an action with its status code. A `default`
response refers to the schema `ProblemDetails`, see [Responses and errors](responses.md#usage-responses).

With `?target=backend`, the document describes the actions of the backend user
interface. This needs a backend user session. A request with the token of an
app gets the status `403`.

The button API documentation in the module
Administration \> Integrations \> API Hub renders this document with
Swagger UI.